Plastics containers

ABSTRACT

An open-topped, thin-walled, disposable plastics container and a method of and tooling apparatus for making the same, the container comprising an inner member having a bottom wall and a sidewall which extends from the bottom wall to the top rim of the container and an outer, heat-insulating member comprising a skirt which depends from the top rim of the container closely alongside the sidewall of the inner member and is formed in one with the inner member and from one and the same piece of thermoplastic sheet material from which the inner member is formed.

States Patent 3,045,887 7 /1962 Caine 220/97 C X 3,353,707 11/1967 Eyles 220/97 C 3,358,879 12/1967 Mueller 220/97 C 3,373,896 3/1968 Davis .1 220/97 C X 3,381,849 5/1968 l(arlsson..... 220/97 C 3,437,233 4/1969 Rathbun... 220/97 C 3,443,714 5/1969 Edwards 220/97 C X 3,452,921 7/1969 Donovan 229/1.5 B X 3,485,412 12/1969 Hawley 220/97 C Primary Examiner-Donald F. Norton Attorney-Ira Milton Jones [72] Inventor Jack M. Schneider Chiltern Lodge, 4 Fame 1111111, Parley, Surrey, England [21] Appl. No. 804,123 [22] Filed Mar. 4, 1969 [45] Patented Oct. 12, 19711 [32] Priority Mar. 8, 1968 [33] Great Britain [31] 11484/68 [54] PLASTllCS CONTAINERS 4 Claims, 20 Drawing Figs.

[52] US. Cl 220/97 C, 229/ 1.5 B [51] llnt. Cl ..lB65d 21/02, 865d 1/00 [50] Field of Search 229/1.5 B; 220/97 C, 97 F; 215/10, 13; 206/65 K [56] References Cited UNITED STATES PATENTS 2,493,633 1/1950 Mart 220/97 C I5 fl 1 1] ll. l li. r-- 1 5 ATENIEU 0m 1 2 1921 ml I25 I6 SHEET Ch BF 7 Q 3 Y 2 1 9 h 5 mm B 7 b 5 B .6 U E /4/ 7 &\ B :5 I l 55 7 E I 9 U I l l. 5 5 H 9 5 PATENTED um 1 2mm SHEET UBUF 17 l 137 I65 I 1' I I 157 m PATENTED mm 1 2 I971 SHEET 1 1 UF PATENTEU um 219?:

SHEET 1 2 OF PATENIEB um 2m SHEET 13 OF ii dLw ll PATENTEDocnznsn 3,612,346

sum mar 17 PATENTEDumemn 3512 4 sum 17UF 17 This invention relates to containers made from thermoplastics material, hereinafter called plastics containers.

More particularly the invention relates to opemtopped thinwalled disposable plastics containers. Such containers may be in the form of cups for solids or liquids, e.g. beverages, or tubs for ice cream. By thin-walled plastics containers is meant containers through the sidewall of which heat is conducted to or from the contents of the container at a rate which makes the container when charged with contents uncomfortable to handle. lt is, of course, most desirable that such containers should be insulated to avoid discomfort to the user of the container. in the past it has been proposed to make a thin-walled plastics container comprising an inner member having a bottom wall and a sidewall extending from the bottom wall to the open top rim of the container and a second member within which the first member is disposed and having bottom and sidewalls closely spaced from the corresponding walls of the first member, the first and second members being connected together by a seam at the top rim of the container. The formation of this known insulating container is wasteful of plastics material and involves the separate formation of the inner and outer members followed by the seaming together thereof.

it is an object of the present invention to form an opentopped, thin-walled disposable plastics container which is economical in the use of plastics material and does not involve the separate formation and subsequent seaming together of the inner and outer members.

The present invention consists in an open-topped, thinwalled disposable plastics container formed from thermoplastic sheet material, comprising an inner member having a bottom wall and a sidewall which extends from the bottom wall to the top rim of the container and an outer, heat-insulating member comprising a skirt which depends from the top rim of the container closely alongside the sidewall of the inner member and is formed in one with the inner member and from one end the same piece of thermoplastic sheet material from which the inner member is formed.

Suitably, the outer heat-insulating member depends from the container rim to a level intermediate the rim and the bottom wall of the inner member.

Advantageously, the inner member of the container is formed on the container rim side of the level to which the outer member depends with an inwardly extending shoulder whereby the container is stackable with like containers by reason of the edge of the outer member of the container remote from the rim of the container engaging the inwardly projecting shoulder of the container therebelow thereby to space the inner member of one container from the inner member of the container therebelow.

in one form of the invention the outer member of the container is formed with an outwardly projecting portion serving in use as a handle for the container.

The invention also consists in the method of forming a thinwalled, open-topped disposable heat-insulated plastics container which includes clamping around an open end of a female tool member a sheet of heated plastics material, drawing the sheet in a direction away from the female tool member thereby utilizing a peripheral part of the sheet to form an outer member of the container open at its end adjacent the female tool member, moving a central part of the sheet in a direction towards the female tool member through the formed outer member, forming the part of the sheet within the formed outer member into an inner container member relative to which the outer member constitutes an insulating skirt depending from the rim of the inner container member in close proximity to part of the inner container member extending from the rim thereof, and, severing the formed container from the plastics sheet.

The invention further consists in tooling apparatus for forming an open-topped thin-walled, disposable plastics container from thermoplastic sheet material comprising a base member formed with a bore and a female tool member slidably fitted within the bore, a clamp for clamping sheet plastics material around an open end of the female tool member, means for projecting the female tool member from and retracting the female tool member into the base member, the projection of the female tool member serving to stretch the sheet plastics material between the frame clamp and the female tool member, a reciprocable knife member movable to engage the sheet material between the clamp and the female tool member having an inner surface which when the knife member is engaged with the sheet material defines the outer member of the container to be formed, means for transferring sheet material between the clamp and the female tool member to the inner surface of the knife assembly to define the outer container member, a reciprocable head member movable to engage the end of the knife member remote from the end thereof which engages the sheet material between the clamp and the female tool member, an assist plug mounted in the head member and reciprocably movable so that with the head member engaged with the knife member and the latter member engaged around the female tool member between the: clamp and the female tool member and the sheet material engaged with the inner surface of the knife member, the assist plug can be projected into the female tool member thereby to pass plastic sheet material through the knife member and into the female tool member for forming an inner member of the container.

The invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 11 is a side elevation to an enlarged scale of an opentopped, thin-walled, disposable plastics container for use as a stackable cup in a vending machine and formed from thermoplastic sheet material.

HQ. in is a fragmentary sectional view, at an enlarged scale, taken on the line lla-lla ofFlG. ll.

HQ. 2 is a sectional view showing a stack of containers of the kind shown in HG. l1.

FlGS. 3 to ill illustrate fragmentary sectional side elevations of tooling apparatus for the manufacture of containers in the form shown in lFlGS. l. and 2, the different views illustrating the location of parts of the tooling apparatus at different stages in the container forming operation.

FlG. 112 is a plan view of a base member of the tooling apparatus illustrated in lFlGS. 3 to ill.

FlG. l3 is an underplan view of a head member of the tooling apparatus of H63. 3 to l l.

FIGS. lid and l5 are respective underplan and topplan views of a knife assembly forming part of the tooling apparatus of H65. ill to ill.

FlG. lib is an under plan view of a frame clamp forming part of the tooling apparatus of FlGS. 3 to ill; and,

FIGS. 117, ill? and E9 illustrate other forms of container which can be produced on tooling apparatus similar to that in accordance with H68. 3 to ill by the mine technique as is hereinafter described for the production of containers according to H6. l.

fhroughout the drawings like parts have been accorded the same references. it should be noted in the following description that the words upper and lower are used with reference to the cup rim being its upper end and the cup base its lower end. However, it should be understood that the orientation of the tooling may be such that the cup is not formed in a vertical position but in a horizontal position.

Referring first to FIG. l a thin-walled open-topped disposable plastics container is in the form of a stackable cup l for use in a vending machine. The cup comprises an inner member 3 having a bottom wall 5 and a sidewall 7 which extends from the bottom wall to the top rim 9 of the cup and an outer heat insulating member comprising a skirt llll which depends from the top rim 9 of the cup closely along the side of an upper part of the sidewall '7 of the inner member 3 and is formed in one with the inner member 3 from one and the same piece of sheet plastics material, suitably, high-impact polystyrene, from which the inner member is formed.

The cup is formed so as to be stackable with similar cups so that when used in a vending machine cups are dispensed one at a time from the bottom of the stack. To this end the inner member 3 is formed in its sidewall 7 with a shoulder 13 located between the rim 9 and the edge 15 of the skirt 11 remote from the rim 9, the shoulder 13 being closer to the edge 15 than to the rim 9. Also, the skirt 11 is formed with longitudinally extending flutes or corrugations (not shown) of shallow depth, while the shoulder 13 is formed with radially extending flutes or corrugations (not shown) of shallow depth. Thus, when the cup 1 is stacked with similar cups the bottom and sidewalls and 7 of the inner member 3 of one cup are spaced from the corresponding parts of the cup therebelow and the bottom edge of the skirt 11 of one cup engages the shoulder 13 of the inner member 3 of the cup therebelow while the bottom of the rim 9 of one cup is spaced a short distance from the top of the rim 9 of the cup therebelow. The longitudinal flutes of the skirt 1 1 of an upper cup thus communicate at one end with the gap between the rims 9 of said upper cup and the cup immediately therebelow. These flutes at their lower ends communicate with the radial flutes in the shoulder 13 of the lower cup. The longitudinal flutes in the skirt 11 of one cup together with the radial flutes in the shoulder 13 of the cup therebelow thus provide communication between atmosphere and the space between the bottom walls 5 and sidewalls 7 of successive cups in the stack. The tendency therefore for the weight of the stack to force out air in the interspace between cups is inhibited and in consequence the tendency in use of the stack in a vending machine to dispense the cups from the bottom of the stack more than one at a time is largely, if not wholly prevented.

It will be observed that the skirt 11 is closely spaced alongside the part of the inner wall 7 of the inner member 3, which extends from the rim 9. The narrow airspace formed between the skirt 11 and the part of the inner wall 7 alongside the skirt 11 affords heat insulation for hot or cold contents of the cup 1. The cup can thus be held by engagement of the users hand with the skirt 11 without the contents of the cup causing discomfort.

The tooling apparatus for making the stackable vending cup 1 comprises a base assembly 21, a head assembly 23, a clamping frame 25 and a knife assembly 27.

The base assembly 21, details of which appear particularly in FIGS. 3 to 12, comprises a baseplate 29 formed with parallel ducts 31 and 33, the ducts 33 alternating with the ducts 31. The ducts 31 are for the conveyance of cooling fluid through the baseplate 29 whilst the ducts 33 are for the conveyance of air as hereinafter described. On the baseplate 29 is formed an array of hollow cylindrical bores 35, each having a lower part 37 of larger diameter than an upper part 39 thereof, the parts 37 and 39 of each bore 35 meeting at a radial shoulder 41. The bores 35 are formed by assembling and securing together a succession of plates 43, 45, 47, 49 and 51. The bores 35 are then formed by forming through the plates 43 to 51 bores of the diameter of the upper part 39 and subsequently counterboring the lower parts 37. Prior to assembly of the plates 43 to 51 the lower surface of the plate 45 is formed with radial grooves 53 which extend from a central deeper groove 55. Thus on assembly of the plates 43 and 45 the grooves 55 form a rectangular lattice of supply ducts through which air can be supplied to or withdrawn from the radial passages formed by the radial grooves 53 connecting the grooves 55 with the bores 35. Similarly, the upper surface of the plate 45 is formed with radial grooves 57 extending from a central groove 59. After assembly of the plates 45 and 47 the grooves 59 form with the lower surface of the plate 47 a rectangular lattice of ducts through which air can be supplied to or withdrawn from the radial passages defined by the grooves 57. A similar rectangular lattice of ducts 61 and radial passages 63 is formed between the plates 47 and 49 and between the plates 49 and 51 is similarly defined a rectangular lattice of ducts 65 and radial passages 67.

Slidably fitted in each cylindrical bore 35 is a female tool or cup cavity member 69 comprising a lower part 71 of a diameter such as to be a sliding fit in the lower part 37 of the bore 35 and an upper part 73 which extends from the part 71 and is a sliding fit in the upper part 39 of the bore 35. The shape of the upper surface of the part 71 and the shape of the inner surface of the part 73 of each cup cavity member 69 corresponds with the bottom wall 5 and lower part of the sidewall 7 of the inner member 3 of the finished cup 1. The inner surface of the part 73 thus tapers slightly downwardly.

The outer surface of the part 71 of each cup cavity member which engages the lower part 37 of the bore 35 is formed with upper, intermediate, and lower annular grooves 75, 77 and 79. in the retracted or lowermost position of the cup cavity member 69 the grooves 77 communicate the air passages 53 by way of passages 81 in the parts 71 with the interior of the cup cavity members 69.

In the projected or uppermost position of each cup cavity member 69 the annular groove 77 thereof communicates the interior of the cup cavity member by way of the passages 81 with the lattice of grooves 59 so that in the projected position of the cup cavity member 69 air can be supplied by way of the lattice of grooves 59 to or withdraw from the interior of the cup cavity member 69. The upper and lower annular grooves 75 and 79 accommodate sealing members (not shown) such as O-rings.

The overall length of the cup cavity member 69 is a little greater than the length of the bore 35 in the base assembly 21 so that in the retracted position of the cup cavity member 69 the latter projects a short distance above the upper surface of the plate 51, this plate 51 being hardened and forming an anvil plate for the knife edges of the knife assembly 27 hereinafter described. The upper end surface 83 of the cup cavity member 69 is formed with radially directed shallow flutes (not shown).

It should be noted that the clearance between the cup cavity members 69 and the anvil plate 51 is sufficient to permit passage of air from the lattice of ducts 65 and the passages 67 between the member 69 and the plate 51. Also, of course, if suction is applied to the ducts 65 air flows into the ducts 65 via the clearance between the anvil plate 51 and the member 69 and thence via the passages 67.

It will be appreciated that in order to project each cup cavity member 69 to its uppermost position, air pressure is supplied to the ducts 33 from which it passes through passages 85 to the underside of the part 71 of the cup cavity member 67.'

At the same time the ducts 59 and 61 are vented to atmosphere so that the differential pressure thus created across the part 71 effects upward movement of the member 69. Venting of the ducts 33 to atmosphere and the supply of air pressure to the ducts 61 and 59 causes retraction of the member 69 to its lowermost position.

Above the base assembly 21 is disposed a clamping frame 25 which serves to secure a heated plastics sheet consisting of high-impact polystyrene from which cups are formed by the tooling apparatus relative to the upper surface of the anvil plate 51 and the upper end of each cup cavity member 69. The clamping frame 25, as seen more particularly in FIG. 16, consists of a plate 91 in which are formed circular apertures 93 which taper upwardly. At the lower side of each aperture 93 the diameter thereof is a maximum and equal to the diameter of each cup cavity member plus the minimum distance between the tops of adjacent members 69. The apertures 93 are coaxial with the bores 35.

Above the clamping frame 91 is disposed the knife assembly 27. The knife assembly consists of knives 101, supported on a frame formed by lower and upper plates 103 and 105. The plates 103 and are formed with corresponding cylindrical apertures within which the knives 101 engage. The plate 103 on its upper surface is formed with grooves 107 which in the a assembled position of the plates 103 and 105 form a rectangular lattice of ducts through which, in operation, cooling fluid is circulated. rearwardly external 

1. An open topped, thin-walled disposable plastic container formed from thermoplastic sheet material, comprising an inner body member having a sidewall that converges downwardly to the bottom of the container from a rim at its top and is formed with an inwardly extending shoulder between the rim and the bottom of the container, and an outer, heat-insulating member comprising a skirt which depends from said rim and embraces at least a substantial part of the inner member and extends convergently downwardly closely alongside the exterior of the latter and is formed in one therewith, said skirt being formed from one and the same piece of thermoplastic sheet material of which the body member is made, said inwardly extending shoulder being at a level between the rim and the Lowermost edges of the skirt, and the outermost diameTer of said skirt at said lowermost edge being less than the outermost diameter of said shoulder, whereby the container is stackable with like containers by reason of its skirt being engageable within the container therebelow, with the lowermost edge of the skirt engaging the inwardly projecting shoulder of said container therebelow, thereby to space the inner member of the container from the inner member of said container therebelow.
 2. A container as claimed in claim 1, wherein the outer member and the shoulder of the inner member are so fluted that when the container is stacked with similar containers, passage means for air to the space between the inner member of successive containers in the stack is provided which leads from between the rims of said successive containers, between the outer member of the upper and the inner member of the lower containers and thence between the shoulder of the lower container and the edge engaged therewith of the outer member of the upper container.
 3. A container as claimed in claim 2, wherein the outer member is formed with longitudinally extending flutes and the shoulder of the inner member is formed with inwardly directed flutes, the flutes on the outer member providing, when the container is stacked with a similar container therebelow, air passage means extending from between the rims of the container to the shoulder of the lower container whilst the flutes in the shoulder of the inner container extend said air passage means between the bottom of the outer member of the upper container and the shoulder of the lower container to the space between the inner members of the containers.
 4. An open-topped, thin-walled, disposable plastic container formed from thermoplastic sheet material, comprising an inner body member having a sidewall that converges downwardly to the bottom of the container from a rim at its top, and an outer, heating-insulating member comprising a skirt which depends from said rim to a level on the side of the bottom wall of the inner container remote from the container rim and extends convergently downwardly closely alongside the exterior of the latter and is formed in one therewith, said skirt being formed from one and the same piece of thermoplastic sheet material of which the body member is made. 